Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Jefferson County, West Virginia
EPA puts Jefferson County in Zone 1, its highest radon zone, and high results are common there: 53.2% of the 898 radon tests reported to CDC (2008 to 2017, laboratory totals) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
53.2%
15.7 pts above WV
- Jefferson
- 53.2%
- WV
- 37.5%
898 tests, 2008 to 2017
Median result
4.4pCi/L
Action level reached
- Jefferson
- 4.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
898
4th of 27 by tests
- Jefferson
- 898
- Berkeley
- 2,888
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in WV
2 of 27
Top quarter
- Jefferson
- 53.2%
- Morgan
- 58.1%
By share, of 27 with 30+ tests
Read a result for Jefferson County
Starts at Jefferson County's median, 4.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.4 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Jefferson County's median reported result, 2008 to 2017.
The data
Jefferson County, At a glance
Jefferson County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Jefferson County in
USGS geologic potential: High across 96% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Jefferson County, 2008 to 2017, laboratory
Under 2 pCi/L: 32%2 to 4 pCi/L: 15%4 pCi/L and above: 53%
Of 898 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 286 | 31.8% |
| 2 to 4 pCi/L | 134 | 14.9% |
| 4 pCi/L and above | 478 | 53.2% |
What these figures count
These are the 898 tests reported to CDC for Jefferson County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Jefferson County, Compared
Jefferson County radon figures, compared
Calculated by Radon411More than half: 53.2% of the 898 radon tests reported to CDC for Jefferson County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 2nd of 27 West Virginia counties with 30 or more tests for the same period. That is 15.7 points above the 37.5% pooled from 55 West Virginia counties.
The median result, 4.4 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 181.0 pCi/L. The rest split 31.8% under 2 pCi/L and 14.9% from 2 to 4 (West Virginia: 37.7% and 24.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 53.2% share point the same way here.
1 of its 5 bordering counties with figures ran higher, led by Washington County, MD at 56.0%; Loudoun County, VA reported 27.4%. Statewide for the same period, Morgan County reported the highest share (58.1%) and Grant County the lowest (9.8%).
CDC's ten-year totals for Jefferson County went from 669 tests (2005 to 2014) to 898 (2008 to 2017), the share going from 55.0% to 53.2%.
Nationally, every county with a figure for the same period pools to 35.7%; Jefferson County sits 17.5 points above it. CDC also counts 44 tests taken after mitigation in Jefferson County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Jefferson County, Geology
The ground under Jefferson County
PredictedMost of the ground under Jefferson County is one class on USGS's geologic map: 95.7% of its land is high radon potential, with 4.3% moderate. 95.1% of it lies in the area the map calls Northern Appalachian Valley and Ridge, to which USGS gives a radon index of 14, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Northern Appalachian Valley and Ridge | Sandstone ridges, shale and limestone valleys, mostly Devonian | High | 14 | 95.1% |
| Blue Ridge | Granite, pegmatite, monazite, schist, and gneiss. | Moderate | 10 | 4.3% |
| Valley and Ridge | Cambrian dolomite, limestone, shale, and sandstone, Silurian-Ordovician limestone, dolomite, shale, and sandstone, Mississippian-Devonian sandstone, shale, limestone, gypsum, and coal. | High | 15 | 0.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Jefferson County beside the ground around it
Jefferson County has more high-potential ground than West Virginia as a whole: 95.7% of its land against 18.7%. Of the 5 counties that border it, 2 have more high-potential ground, Frederick County, VA the most at 100%.
The map rates the ground, not the air in any home.
Local help
Jefferson County, Local resources
Radon testing and mitigation in Jefferson County
- OEHS Radon ProgramOEHS Radon Program, run by WV DHHR OEHS Radiation, Toxics & Indoor Air Division, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in West Virginia.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
West Virginia residents can request a free Radon Test Kit by emailing Radon@wv.gov or calling 304-352-5039
- Compare kits
- Professionals in West Virginia35 professionals are listed in West Virginia.
What West Virginia's program says
- Phone
- 304-352-5039
- Radon@wv.gov
- Licensing of radon professionals
Complete listings of professionals licensed to perform Asbestos, Lead, Radon and Clandestine Drug Laboratory Remediation activities in West Virginia.
What it means
Jefferson County, Questions
Questions about radon in Jefferson County
Are radon levels high in Jefferson County?
Over the 2008 to 2017 laboratory totals, 53.2% of the radon tests reported to CDC for Jefferson County, West Virginia were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.4 pCi/L. Of 27 West Virginia counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 37.5%.
Which counties border Jefferson County?
Jefferson County borders 5 counties: Berkeley County, WV, Clarke County, VA, Washington County, MD, Loudoun County, VA and Frederick County, VA.
Products
Jefferson County, Products
Testing a home in Jefferson County
In Jefferson County, 53.2% of 898 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 37.5% pooled across West Virginia. In Zone 1 the year-round level in Jefferson County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
Monitor
EcoQube Wi-Fi continuous radon monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi
- App only
Method: Ion chamber
First reading: Within 10 minutes
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Jefferson County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Jefferson County
Explore
Jefferson County, Bordering counties
Counties bordering Jefferson County
Calculated by Radon411- Radon levels in Washington County, MDEPA zone 1
56.0%at or above 4 pCi/L
Median 5.2 pCi/L · 1,259 tests · 2.8 points above Jefferson County
- Radon levels in Berkeley County, WVEPA zone 1
50.7%at or above 4 pCi/L
Median 4.0 pCi/L · 2,888 tests · 2.5 points below Jefferson County
- Radon levels in Clarke County, VAEPA zone 1
47.7%at or above 4 pCi/L
Median 3.5 pCi/L · 350 tests · 5.5 points below Jefferson County
- Radon levels in Frederick County, VAEPA zone 1
44.1%at or above 4 pCi/L
Median 3.3 pCi/L · 2,451 tests · 9.1 points below Jefferson County
- Radon levels in Loudoun County, VAEPA zone 2
27.4%at or above 4 pCi/L
Median 1.8 pCi/L · 4,457 tests · 25.8 points below Jefferson County
Jefferson County, Cities and towns
Cities and towns in Jefferson County
Jefferson County is growing: the Census Bureau puts it at 63,102 residents on July 1, 2025, up 9.2% from 57,790 in 2020. That works out to 301 people per square mile of land. No town dominates: Charles Town, the largest, has 9,329 residents, 14.8% of the total. Together its 5 incorporated places hold 30.0% of those residents; the other 70.0% live outside any of them. Testing is reported here more often than across the state: CDC's 898 reported tests for 2008 to 2017 come to 14.2 for every 1,000 residents (2025 estimate), against 5.7 for West Virginia.
From Charles Town to Harpers Ferry, CDC publishes no figure by town: each reads Jefferson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Charles Town | 9,329 | +42.9% | 14.8% |
| Ranson | 6,853 | +25.1% | 10.9% |
| Shepherdstown | 1,522 | −0.7% | 2.4% |
| Bolivar | 983 | −5.2% | 1.6% |
| Harpers Ferry | 266 | −1.8% | 0.4% |
5 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Jefferson County, Homes
Homes in Jefferson County
Jefferson County is a place of houses on their own lots: 79% of its 24,276 homes are detached single-family houses, against 71% across West Virginia. Much of Jefferson County is recent building: 34% of its homes have gone up since 2000 and the middle year built is 1990, against 1976 for West Virginia. Owners live in 79% of the occupied homes (West Virginia: 74%), so for most households a test and a fix are their own to order.
| Homes | Jefferson County | West Virginia |
|---|---|---|
| Housing units | 24,276 | 859,653 |
| Detached houses | 79% | 71% |
| In buildings of 5 or more | 5% | 8% |
| Mobile homes | 6% | 14% |
| Built before 1960 | 15% | 33% |
| Built since 2000 | 34% | 18% |
| Middle year built | 1990 | 1976 |
| Owner-occupied | 79% | 74% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.